959e627208
The scoping rules around %template have been specified and enforced.
The %template directive for a class template is the equivalent to an
explicit instantiation of a C++ class template. The scope for a valid
%template instantiation is now the same as the scope required for a
valid explicit instantiation of a C++ template. A definition of the
template for the explicit instantiation must be in scope where the
instantiation is declared and must not be enclosed within a different
namespace.
For example, a few %template and explicit instantiations of std::vector
are shown below:
// valid
namespace std {
%template(vin) vector<int>;
template class vector<int>;
}
// valid
using namespace std;
%template(vin) vector<int>;
template class vector<int>;
// valid
using std::vector;
%template(vin) vector<int>;
template class vector<int>;
// ill-formed
namespace unrelated {
using std::vector;
%template(vin) vector<int>;
template class vector<int>;
}
// ill-formed
namespace unrelated {
using namespace std;
%template(vin) vector<int>;
template class vector<int>;
}
// ill-formed
namespace unrelated {
namespace std {
%template(vin) vector<int>;
template class vector<int>;
}
}
// ill-formed
namespace unrelated {
%template(vin) std::vector<int>;
template class std::vector<int>;
}
When the scope is incorrect, an error now occurs such as:
cpp_template_scope.i:34: Error: 'vector' resolves to 'std::vector' and
was incorrectly instantiated in scope 'unrelated' instead of within scope 'std'.
Previously SWIG accepted the ill-formed examples above but this led to
numerous subtle template scope problems especially in the presence of
using declarations and using directives as well as with %feature and %typemap.
Actually, a valid instantiation is one which conforms to the C++03
standard as C++11 made a change to disallow using declarations and
using directives to find a template.
// valid C++03, ill-formed C++11
using std::vector;
template class vector<int>;
Similar fixes for defining classes using forward class references have
also been put in place. For example:
namespace Space1 {
struct A;
}
namespace Space2 {
struct Space1::A {
void x();
}
}
will now error out with:
cpp_class_definition.i:5: Error: 'Space1::A' resolves to 'Space1::A' and
was incorrectly instantiated in scope 'Space2' instead of within scope 'Space1'.
40 lines
748 B
OpenEdge ABL
40 lines
748 B
OpenEdge ABL
%module namespace_template
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namespace test {
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template<typename T> T max(T a, T b) { return (a > b) ? a : b; }
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template<typename T> class vector {
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public:
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vector() { }
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~vector() { }
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};
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}
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namespace test2 {
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using namespace test;
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%template(maxshort) max<short>;
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%template(vectorshort) vector<short>;
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}
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namespace test3 {
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using test::max;
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using test::vector;
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%template(maxlong) max<long>;
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%template(vectorlong) vector<long>;
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}
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namespace test4 {
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using namespace test;
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typedef int Integer;
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}
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namespace test4 {
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%template(maxInteger) max<Integer>;
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%template(vectorInteger) vector<Integer>;
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}
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using namespace test;
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namespace test5 {
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%template(maxdouble) max<double>;
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%template(vectordouble) vector<double>;
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}
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